With the fast development of mobile terminal, the amount of mobile phone users is increased day by day. In order to prevent hackers from carrying out download operation on the mobile phone through a computer and from accessing the internal procedure of the memory of the mobile terminal by accessing the master chip of the mobile phone so as to crack the lock network locking card function of the mobile phone, the mobile phone usually needs to be protected through encryption added by a manufacturer.
In the prior art, Message-Digest Algorithm 5 (MD5) is usually adopted as cryptographic algorithm for carrying out encryption on the internal procedure of the memory of the mobile terminal. Since the cryptographic algorithm is an exhaustive encryption algorithm, when the mobile phone is turned on, the encrypted procedure is required to be decrypted before the mobile phone runs, which leads to long turn-on time of the mobile phone due to long decryption time. To reduce the turn-on time of the mobile phone, just a few important codes in the internal procedure of the memory of the mobile phone are encrypted under normal conditions. However, for the hackers familiar with the internal procedure of the memory of the mobile phone, the encrypted code segment is easily replaced by a substitute code segment to run the whole procedure, so that download and access operations performed to the mobile phone is performed by the computer through the connector of the mobile phone.
Another encryption manner combined with a platform is as follows: after the serial number of the chip of the mobile phone is bond with that of the memory of the mobile phone, a ciphertext is stored in the memory, and the serial numbers of the ciphertext are verified after every turn-on operation; if the serial numbers obtained after verifying are identical to that of the master chip of the mobile phone and that of the memory of the mobile phone, the procedure runs. However, the encryption manner is still adopted for the encryption of a few code segments, and similarly can be decrypted by the hackers; therefore, the security of the mobile phone is reduced.
The above encryption manners are both adopted for the encryption of a few code segments in the internal procedure of the memory of the mobile phone, and belong to software encryption manner; the encrypted procedure can be decrypted as long as the encrypted code segment is replaced by the substitute code segment by the hackers, and the download and access operations can be performed to the mobile phone through the connector of the mobile phone, so as to seriously influence the security of the mobile phone; therefore, it is especially important to look for a more high-effective encryption manner.